System of control.



R. E. lHELLMUND, SYSTEM OFCONTROL APPLICATION FILED sEPT.9, I9I5.

1 ,246,424. Patented Nov, 13, 1917.

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RUDOLF E. HELLMUND, F ITTSBURGH, PENNS LVANIA., ASSIGNOR '10 WESTIN'G- HUSE ELECTRIC AND MANUFACTURING COMPANY, It. CBORATION 0F PENN'- SYLVMM..

Speciication of Letters Patent.

srsrniu or courent.

Patented Nov. i3, lg3d?.-

appneaueaeiea september e, reis. serial No. renee.

To @ZZ 'whom t may concern:

Be it known that l, lltnnonr HELLMUND,

a subject or the German Empire, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented a new and useful improvement in Ir-Jystenis of Control, ci which the :tollowage battery or motor-generator, has been rel quired during the vregencrating period, for the reason that a straight seit-excited series generator is not stable or reliable in operation and also because the series-type eld windings of electric railwayinotors are not well adapted for shunt excitation, inasmuch es suoli motors are usually operated as series motors during propulsion conditions,A

and the eld windings are accordingly ole-v signed for relatively heavy currents and comprise relatively few turns. Consequently, a straight shunt excitation would be possible only by the addition ci a special :deld winding for tliis'purpose which, by reason et the space limitations prevailing with railway motors, particularly because ci the crowded condition of the under sureces et the do-ors of modern electric railwey vehicles, is usually impractical.

According to my present invention, I provide ineens tor permitting shunt excitation e plurality of regenerating dynamo-electric machines without necessitating excesswe losses in the exciting circuit and without reeuiring the 'use of any additional eld windin s or external source o/ener or a better understandin gl the nature of my resent invention, re erence may be had to t e following description and the accompanying drawing in which Figure 1 is a schematic diagram of an electrical control system embodying a form of my invention;

Fig. 2 yis a similar diagram of a modified forni of the system shown in Fig. l; Figs. 3 and l are schematic diagrams of control systems embodying other forms of my invention in which dynamoters are substituted for the motor-generator sets of the systems illustrated in Figs. l and 2.

Referring to Figure l, the system shown comprises a plurality of supply-circuit conn ductors respectively marked rlrolley and Ground, a plurality of main dynamo-electric machines that are respectively provided 'with armatures Ai, A2,* A8 und and series-type field magnet windings F1, F2, F8 and F4, an auxiliary motor-generator set comprising an armature lll, a series eld winding` MF therefor, e second armature winding G that is mechanically associated with the armature M in any suitable manner, and a shunt field winding GF for the armature winding G; e resistor R1 thet is disposed in series-circuit relation with the field winding MF; a second resistor R2 that is connected in circuit with the field 'winding GF across the armature winding G; and a suitable switching device or controller C, that is conventionally illustrated here, for the purpose 'ot suitably governing the general operation of the system.

All of the main dynamoelectric machinearmatures A3 to At, inclusive, are connected in parallel-circuit relation between the supply-circuit conductors Trolley and Ground, while the main eld windings F1 to F4, inclusive, are connected in seriescircuit relation with the resistor R1, the field winding MF and the armature windlng M across the supply circuit. The armature vvinding G is connected directly tov the supply-circuitconductors.

By the use of the connections illustrated, approximately one quarter of the total regenerated current traverses the exciting circuitof the mainield windings However, such a value oi currentV requires a volta e that is materially lower than that availab e and, consequently, if plain rheostatic control were employed in the exciting circuit, relatively heavy losses would occur. By connecting the armature winding M in cirn cuit in such manner that it acts as a bucker, that is to say, sothat its voltage opposes the winding.

voltage of the regenerating machines and assists the voltage of thel supply circuit, the exciting current for the regenerating machines is reduced to a suitable value without entailing any heavy losses, inasmuch as all of the surplus exciting energy that is not necessary to overcome the relatively small mechanical and electrical losses of the motor-generator set is returned to the supply circuit by the armature winding G, whereby 'a relatively efficient and economical system of regenerative control is obtained.

It will be understood that regulationl of the regenerative operation may be effected by suitable manipulation of the resistors R1 and R2 during the period that the speeds of the main' dynamo-electric machines are gradually decreasing, or in any other suitable manner.

Reference may now be had to Fig. 2, wherein the only difference from the system shown in Fig. 1 resides in the connection of the .armature winding G between the negative supply-circuit conductor, Ground, and a oint intermediate the armature winding Mpand the'ield windings of the main dynamo-electric machines, while the armature winding M is provided with,a shunt `field winding MF1 that `is connected through a variableresistor R3 across the armature In this way, the surplus exciting energy that is transmitted from the armature M to the armature G is returned to the exciting circuit comprising the main lield windings, whereby .-a lmotor-generator Vset of still smaller capacity than is necessary in the system shown in Fig. 1 may be employed.

In Fig. 3, the armatures and ield windings of the main dynamo-electric machines are .connected in the manner already described, and a dynamotor is employed in place ofthe motor-generator set mentioned above for the purpose of regulating the excitation current for the main machine.

The dynamotor shown comprises mechanically-connected armature windings M1 and G1 and a common field-magnet winding DF that is connected across the armature winding G1. A resistor R4, the sections of which may be respectively shortcircuited by switches 1 and 2, is connected between the armature winding G1* and the negative supply-circuit conductor, Ground.

The armature winding M1 is connected in series-circuit relation with the main field windings F1.to F4, inclusive, across the su. ply circuit, while the amature' windin 'G1 l l 1s adapted to return the surplus exciting- 60 circuit ener n tothe supply circuit, in a manner simi ar to that described in connection with Fi 1, and no'further description thereof is be ieved to be necessary.

In Fig. 4 the dynamotor connections arel modified in the following manner: the armature windings M1 and G1 are disposed in seriescircuit relation with a variable resistor Rx5 across the supply circuit, while the dynamotor field winding DF is connected across the two series-connected armature windings M1 and G1. l

The armature winding G1 is thus adapted to return the surplus exciting-circuit energy to the main field windings F1 to F, inclusive, inthe -manner already set forth in connection with Fig. 2. In this ease, the dynamotor may be of smaller capacity than that necessary for operation in connection with the system shown in Fig. 3.

I do not wish to be restricted to the specic circuit connections or arrangement of parts herein set forth, as various modifications thereof may be made without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations shall be imposed in the appended claims.

' I claim as my invention: e

1. In a system of control, the combination with a plurality of main momentum-driven dynamo-electric machines severall havi armatures and field ma et win ings, o means for connecting sai armatures in parallel-circuit relation, means for connecting said field windings in series-circuit relation, a plurality of mechanically associated auxiliary armature windings, means for connectas are indicated mg oneofvsaicl'auxiliary windings in series- Y said second armature winding to' return the energy derived from said bucker tov certain circuits. l

2. In a system of control, the combination with a supply circuit and a plurality 'of main momentum-driven dynamo-electric machines` severally having armatures and field-magnet windmgs, of means vforconn'ecting said armatures in parallel-circuit relation across said su ply circuit, means for connecting said eld) windin in series-cir- 'cuit relatlon, a plurality o mechanically'- associated armature windin means for connecting one of said auxi lary windin in series-clrcuit relation with said lield win ings across the supply circuit to act as a bucker and employ the,energy not needed for field excitatlom'and'v means for 'connecttlienergy derived from saidbnckertosthe supplglclrcuit.

said second armature winding togreturn' a system of control,'the combination associated armature wind' means for series-connected field windings to return the connecting one of said auxi 'ary windings energy derived from saidrbucker thereto. in series-circuit relation with said eld wind- In testimony whereof, I have hereunto 104 .ings across the supply circuit to act as a subscribed my name this 31st day of Aug., 5 bucker` and to employ the energy not needed 1915. Y

for field excitation, and means for connect-A i ing said second armature winding across the RUDOLF E. HELLMUND. 

